Why do male seahorses get pregnant?

Male seahorses carry the eggs in a brood pouch after the female deposits them there during mating. Inside the pouch, the male provides a protected, regulated environment where the embryos develop until he gives birth to fully formed young. This unusual system is rare in animals and is one reason seahorses have fascinated biologists for years. It also means the male invests heavily in gestation, while the female can produce the next batch of eggs sooner. The arrangement helps explain why seahorses are often cited as one of the most unusual fish in the ocean.